Pyruvate orthophosphate dikinase (referred to hereinafter as "PPDK") is an enzyme which catalyzes a reaction for forming adenosine 5'-triphosphate (ATP), pyruvic acid and phosphoric acid from adenosine 5'-monophosphate (AMP), phosphoenol pyruvic acid and pyrophosphoric acid. This enzyme is used for quantification of, for example, pyrophosphoric acid (Japanese Patent Appln. LOP Publication No. 12300/86). Further, in reference to bioluminescence method, this enzyme is utilized to maintain a high level stable emission without decaying for a long period of time (Kashiwabara et al., 116.sup.th Anneal Meeting of Pharmaceutical Society of Japan, Lecture Summary 4, page 154).
Eisaki et al. found a novel PPDK in a strain belonging to the genus Microbispora, which is stable in storage in a low-temperature range and resistant to freezing and thawing (Japanese Patent Appln. LOP Publication No. 168375/86). However, a problem has been that only a small amount of PPDK can be produced when this strain is cultured to produce the enzyme. Another problem is that this strain must be cultured for about 3 days during which contamination with other microorganisms can easily occur.